Maine (ME) Propane & Natural Gas
Appliance Connection & Service Technician:
200 Practice Exam Questions & Study Guide
1. According to Maine Fuel Board rules, what is the maximum BTU
input per appliance that this specific license allows a technician to
service?
A) 100,000 BTU
B) 250,000 BTU
C) 500,000 BTU
D) 1,000,000 BTU
Answer: C
Explanation: The Appliance Connection & Service Technician license
in Maine is limited to appliances with an individual input of 500,000
BTUs or less.
2. Which National Fire Protection Association (NFPA) standard is the
primary reference for the installation of gas piping and appliances?
A) NFPA 31
B) NFPA 54
C) NFPA 70
D) NFPA 211
Answer: B
Explanation: NFPA 54 is the National Fuel Gas Code, which serves as
the legal basis for gas installation and venting requirements in Maine.
3. What is the specific gravity of Propane (LP) gas?
A) 0.60
B) 1.00
C) 1.50
D) 2.10
Answer: C
Explanation: Propane has a specific gravity of 1.50, meaning it is
heavier than air (1.0) and will settle in low areas if a leak occurs.
4. A thermocouple in a standing pilot system produces approximately
how many millivolts when heated correctly?
,A) 15 to 30 mV
B) 250 to 750 mV
C) 120 Volts
D) 24 Volts
Answer: A
Explanation: A standard thermocouple produces a small DC current
between 15 and 30 millivolts, enough to hold the safety magnet open
in the gas valve.
5. In a 120V AC electrical circuit, which wire color is traditionally used
to represent the "Neutral" or grounded conductor?
A) Black
B) Green
C) White
D) Red
Answer: C
Explanation: Per the NEC (National Electrical Code), white is used for
neutral, black for hot, and green or bare copper for ground.
6. What is the required minimum manifold pressure for most Natural
Gas furnaces?
A) 3.5" WC
B) 11.0" WC
C) 0.5 PSI
D) 7.0" WC
Answer: A
Explanation: Most natural gas residential appliances are designed to
operate at 3.5 inches of Water Column (WC) at the burner manifold.
7. A "Sediment Trap" (Drip Leg) must be installed:
A) Before the main gas shut-off valve.
B) After the appliance gas control valve.
C) As close to the appliance inlet as practical, downstream of the shut-
off valve.
D) Only if the gas is "wet" gas.
Answer: C
Explanation: NFPA 54 requires a sediment trap to prevent debris or
,moisture from entering and damaging the appliance's sensitive gas
control valve.
8. What is the expansion ratio of liquid propane to propane gas?
A) 10:1
B) 100:1
C) 270:1
D) 600:1
Answer: C
Explanation: One gallon of liquid propane expands into 270 cubic feet
of gas, making liquid leaks significantly more hazardous than vapor
leaks.
9. Which tool is used to measure the resistance in an electrical
component like a gas valve coil?
A) Voltmeter
B) Ammeter
C) Ohmmeter
D) Manometer
Answer: C
Explanation: An ohmmeter (often part of a multimeter) measures
electrical resistance (Ohms). A reading of infinity indicates an open
circuit (broken coil).
10. Carbon Monoxide (CO) is a byproduct of:
A) Complete combustion.
B) Incomplete combustion.
C) High gas pressure.
D) Excess primary air.
Answer: B
Explanation: CO is produced when there is insufficient oxygen or a
flame is "quenched," preventing the carbon in the fuel from turning into
CO2.
11. What is the purpose of a "Limit Switch" on a forced-air furnace?
A) To turn the fan on when it gets hot.
B) To shut off the gas if the heat exchanger overheats.
C) To regulate the room temperature.
D) To ignite the burners.
, Answer: B
Explanation: The limit switch is a safety device that opens the
electrical circuit to the gas valve if the air inside the furnace exceeds a
safe temperature.
12. When using a manometer to check for gas leaks (Pressure Drop
Test), how long must the pressure hold without dropping?
A) 1 minute
B) 3 minutes
C) 10 minutes
D) 24 hours
Answer: C
Explanation: Standard practice and many local codes require a
minimum 10-minute duration for a pressure drop test on existing
systems.
13. A Category I appliance is defined as one that operates with:
A) Positive vent pressure and high heat.
B) Non-positive vent pressure and a vent gas temperature above the
dew point.
C) Positive vent pressure and low heat.
D) Condensing flue gases.
Answer: B
Explanation: Category I appliances (like standard atmospheric
furnaces/water heaters) rely on natural draft (non-positive pressure)
and do not produce condensation in the vent.
14. What is the approximate BTU content of one cubic foot of Natural
Gas?
A) 500 BTU
B) 1,000 BTU
C) 2,500 BTU
D) 21,500 BTU
Answer: B
Explanation: Natural gas typically provides 1,000 to 1,050 BTUs per
cubic foot, while Propane provides approximately 2,500 BTUs.
15. If a technician finds a cracked heat exchanger in a furnace, what is
the required action?
Appliance Connection & Service Technician:
200 Practice Exam Questions & Study Guide
1. According to Maine Fuel Board rules, what is the maximum BTU
input per appliance that this specific license allows a technician to
service?
A) 100,000 BTU
B) 250,000 BTU
C) 500,000 BTU
D) 1,000,000 BTU
Answer: C
Explanation: The Appliance Connection & Service Technician license
in Maine is limited to appliances with an individual input of 500,000
BTUs or less.
2. Which National Fire Protection Association (NFPA) standard is the
primary reference for the installation of gas piping and appliances?
A) NFPA 31
B) NFPA 54
C) NFPA 70
D) NFPA 211
Answer: B
Explanation: NFPA 54 is the National Fuel Gas Code, which serves as
the legal basis for gas installation and venting requirements in Maine.
3. What is the specific gravity of Propane (LP) gas?
A) 0.60
B) 1.00
C) 1.50
D) 2.10
Answer: C
Explanation: Propane has a specific gravity of 1.50, meaning it is
heavier than air (1.0) and will settle in low areas if a leak occurs.
4. A thermocouple in a standing pilot system produces approximately
how many millivolts when heated correctly?
,A) 15 to 30 mV
B) 250 to 750 mV
C) 120 Volts
D) 24 Volts
Answer: A
Explanation: A standard thermocouple produces a small DC current
between 15 and 30 millivolts, enough to hold the safety magnet open
in the gas valve.
5. In a 120V AC electrical circuit, which wire color is traditionally used
to represent the "Neutral" or grounded conductor?
A) Black
B) Green
C) White
D) Red
Answer: C
Explanation: Per the NEC (National Electrical Code), white is used for
neutral, black for hot, and green or bare copper for ground.
6. What is the required minimum manifold pressure for most Natural
Gas furnaces?
A) 3.5" WC
B) 11.0" WC
C) 0.5 PSI
D) 7.0" WC
Answer: A
Explanation: Most natural gas residential appliances are designed to
operate at 3.5 inches of Water Column (WC) at the burner manifold.
7. A "Sediment Trap" (Drip Leg) must be installed:
A) Before the main gas shut-off valve.
B) After the appliance gas control valve.
C) As close to the appliance inlet as practical, downstream of the shut-
off valve.
D) Only if the gas is "wet" gas.
Answer: C
Explanation: NFPA 54 requires a sediment trap to prevent debris or
,moisture from entering and damaging the appliance's sensitive gas
control valve.
8. What is the expansion ratio of liquid propane to propane gas?
A) 10:1
B) 100:1
C) 270:1
D) 600:1
Answer: C
Explanation: One gallon of liquid propane expands into 270 cubic feet
of gas, making liquid leaks significantly more hazardous than vapor
leaks.
9. Which tool is used to measure the resistance in an electrical
component like a gas valve coil?
A) Voltmeter
B) Ammeter
C) Ohmmeter
D) Manometer
Answer: C
Explanation: An ohmmeter (often part of a multimeter) measures
electrical resistance (Ohms). A reading of infinity indicates an open
circuit (broken coil).
10. Carbon Monoxide (CO) is a byproduct of:
A) Complete combustion.
B) Incomplete combustion.
C) High gas pressure.
D) Excess primary air.
Answer: B
Explanation: CO is produced when there is insufficient oxygen or a
flame is "quenched," preventing the carbon in the fuel from turning into
CO2.
11. What is the purpose of a "Limit Switch" on a forced-air furnace?
A) To turn the fan on when it gets hot.
B) To shut off the gas if the heat exchanger overheats.
C) To regulate the room temperature.
D) To ignite the burners.
, Answer: B
Explanation: The limit switch is a safety device that opens the
electrical circuit to the gas valve if the air inside the furnace exceeds a
safe temperature.
12. When using a manometer to check for gas leaks (Pressure Drop
Test), how long must the pressure hold without dropping?
A) 1 minute
B) 3 minutes
C) 10 minutes
D) 24 hours
Answer: C
Explanation: Standard practice and many local codes require a
minimum 10-minute duration for a pressure drop test on existing
systems.
13. A Category I appliance is defined as one that operates with:
A) Positive vent pressure and high heat.
B) Non-positive vent pressure and a vent gas temperature above the
dew point.
C) Positive vent pressure and low heat.
D) Condensing flue gases.
Answer: B
Explanation: Category I appliances (like standard atmospheric
furnaces/water heaters) rely on natural draft (non-positive pressure)
and do not produce condensation in the vent.
14. What is the approximate BTU content of one cubic foot of Natural
Gas?
A) 500 BTU
B) 1,000 BTU
C) 2,500 BTU
D) 21,500 BTU
Answer: B
Explanation: Natural gas typically provides 1,000 to 1,050 BTUs per
cubic foot, while Propane provides approximately 2,500 BTUs.
15. If a technician finds a cracked heat exchanger in a furnace, what is
the required action?
